Improving the performance of Ge2Sb2Te5 materials via nickel doping: Towards RF-compatible phase-change devices. - Guo, Pengfei; Burrow, Joshua A.; Sevison, Gary A.; Sood, Aditya; Asheghi, Mehdi; Hendrickson, Joshua R.; Goodson, Kenneth E.; Agha, Imad; Sarangan, Andrew (Applied Physics Letters, 2018)